Electronic devices communicate with each other using a number of different methods. For example, integrated circuits (ICs) use input and output pins to communicate with other ICs or other devices. Such input and output pins are connected to other components or ICs using communication lines such as wires, traces, cables, etc. Because such communication lines connecting the devices carry information, they are natural targets for hackers or other parties that are interested in getting unauthorized access to the information being communicated on such communication lines. For example, by tapping an external lead onto a wire connecting two devices, a third party can access information being communicated on that wire and/or affect the information being communicated between the two devices. Furthermore, such communication lines between electronic devices are also the likely locations for integrating external unauthorized devices such as probes, which also affect the performance of the electronic devices and the ICs. For example, addition of the external components drains power, therefore, affecting the length of battery usage.
The security of the communications between the devices on a circuit board can be improved by encrypting the communication between the devices on the circuit board. However, such encryption does not necessarily prevent simple intrusion or attacks. Furthermore, such encryption techniques also do not defend against a determined adversary that is interested in capturing a large volume of communications for off-line decryption analysis. Moreover, using such encryption techniques adversely affects the speed of communication between the devices and the time necessary for processing of the communicated information.